Patent GB-906793-A (GB)
Title: Method of and apparatus for building tires
IPC: B29D30/32
Filed: 1960-08-15
Abstract: 906,793. Tyre-building machines. GOODYEAR TIRE & RUBBER CO. Aug. 15, 1960 [Aug. 25, 1959], No. 28136/60. Class 144 (1). In a tyre-building machine in which plies of rubberized tyre fabric 113 are wrapped around an expandable drum 1, consisting of three sections expandable by air bags 13, the outer two sections of which are axially movable relative to the mid-section, with their end sections 114 projecting on to air bags 53 at each end of the drum, the drum 1 is first expanded to form shoulders, bead rings 112 are placed against the shoulders and the bags 53 are inflated firstly to move the end sections 114 away from the drum and into engagement with the inner periphery of the bead rings 112 and then restraining and pushing members 63 are moved inwardly towards the drum to distort the air bags 53 in order to stitch the end sections 114 around the bead rings 112 and over the plies wrapped round the drum 1. Drum assembly.-As shown, the drum 1 is mounted on a rotatable cantilevered shaft 2 and comprises three spiders 14, 14a and 14b on which are mounted a number of spring- loaded sector elements 20 which are movable radially outwards by the inflation of air bags 13. The outer spiders 14, 14b are movable towards or away from the central spider 14a by means of a number of left and right-handed screwthreaded shafts 17 interconnected by gears 42, 43. The air for the inflation of the bags is supplied through the centre of the shaft 2. Radially and axially overlapping arcuate coverplates 37 are attached to the outer surfaces of the segments 20 to provide a continuous cylindrical surface for a cylindrical flexible stretchable cover 39 which completely encloses the plates 37. Spacer elements, Figs. 4 and 5 (not shown), may be secured to the outer surface of the elements 20 to increase the diameter of the drum 1. Bead setters.-As shown in Figs. 1, 10 and 11, carriages 66, 66a, mounted on slide bars 69 and movable towards and away from each other by means of air cylinders 71, 74, carry radially adjustable bead holding elements 95. Each element 95 has a recessed surface 96, 97 to engage a bead 112 and inclined ends which engage inclined surfaces 99 of members 100 secured to a lock plate 102. Pins 104 secured to the elements 95 engage tangentially inclined slots 103 in rings 105 so that when the ring 105 is rotated the elements 95 are moved radially inwards or outwards to engage a given diameter bead ring 112. The lock plate 102 is provided with a number of radiallyextending lugs 108 which engage similar lugs on a base plate 110 to form a bayonet lock to facilitate replacement of the bead setters to suit different size beads. Ply turnover and stitching means.-Attached to each end of the drum 1 are rigid cylindrical supports 50 on which are secured by a portion 54 an annular flexible inflatable bag 53. The portion 61 of the bag 53 adjacent the drum is made of material which is more flexible than the rest of the bag 53. After the bead ring 112, Fig. 18 (not shown), has been stitched against the shoulders formed by the ply 113, due to the expansion of the drum 1, the bag 53 is inflated and initially, due to the more flexible portion 61, the bag 53 expands radially outwards and away from the drum to pull the ply endings 114 axially outwards from the plies 113 and at the same time to press the ply endings 114 radially outwards to stitch the ends 114 to the inner periphery of the bead 112. Continued inflation of the bag 53 causes the portion 61 to straighten radially outwards, Fig. 21, to stitch the ply endings 114 against the outer axial face 124 of the bead ring 112. The straining and pushing members 63 mounted on the bead setters 95 and having inclined inner faces 121, 122, are now moved towards one another by air cylinders 71, 74 to distort the bag 53, Fig. 22, to stretch the ply endings 114 over the outer periphery 126 of the bead ring 112 and the plies 113 surrounding the expanded drum 1. Consolidating.-After the carriages 66, 66a are returned to the position shown in Fig. 1 and the bags 53 deflated a tyre thread is then wrapped around the ply 113 and face stitches 84 are moved away from one another towards the end of the drum to stitch the tyre tread to the plies 113. The drum 1 is now collapsed and the carriage 66 is tilted by an air cylinder 83, Fig. 1, to enable the tyre to be removed from the drum. Suitable controls may be provided for affecting operation of the cylinders 71, 74 and 83 as well as the motor effecting the rotation of the drum in the desired time sequence relationship. Specification 906,794 is referred to.